The often-wonderful This American Life show covered this topic quite recently. They tried to find out what the deal was with Intellectual Ventures and their ilk, and made some surprising discoveries. (I don't want to give away any spoilers.)

Pretty much everyone, including OSS software developers, desire the benefits of copyright. The way that the MPAA/RIAA goes about enforcement is definitely out of control, but the fundamental issue is okay.

Software patents, on the other hand, are (at least) well in the the grey area surrounding "what should be patentable". A business process, a mathematical formula, a procedure, an idea? How ethereal can something be and still be someone's property?

The MAFIAA are trying to change the rules to suit their own interests. Patent trolls, on the other hand, are functioning just fine with the rules the way they are.